Radiator fin construction



Sept. 19, 1933; w. c. RITTER RADIATOR FIN CONSTRUCTION Filed Oct. 12, 1931 ATTO RN EY-S s extending transversely of the tubes for Patented Sept. 19, 1933 y 1,927,325 l RADIATOR FIN CONSTRUCTION William C. Ritter, Detroit, Mich., assignor to Long'Manufacturing Company, Detroit, a corporation of Michigan Mich.,

Application October- 12, 1931. Serial No. 568,477

3 Claims.

This invention relates generally to heat exchange units and refers more particularly to radiator constructions of the type having a plurality of tubes for the cooling medium and fins dissipating the heat of the latter.

One of the principal objects of this invention is to increase the efficiency of `heat exchangev units of the foregoing type by providing means on the iins for creating a turbulence in the fluid stream between the tubes and thereby direct fluid from the stream into contacting relation with the tubes.

A further advantageous feature of'this invention which contributes materially to increasing the efficiency of the heat exchange unit consists in the provision of means of the type set forth in the preceding paragraph so designed as to create a turbulence in the fluid stream Without restricting the passage of the fluid through the unit.

The foregoing as well as other objects will be made more apparent as this description proceeds, especially when considered in connection with the accompanying drawing, wherein:

Figure 1 is a fragmentary front elevational view of a heat exchange unit constructed in accordance with this invention;

Figure 2 is a plan view of the construction shown in Figure 1;

Figure 3 is an enlarged perspective view showing my improved fin construction;

Figure 4 is an enlarged longitudinal section taken substantially on the plane indicated by the line '4 4 of Figure 2;

Figure 5 is an enlarged cross section taken on the line 5-5 of Figure 2.

For the purpose of illustrating the present invention, I have selected a heat exchange unit commonly referred to in the art as a radiator comprising a series of vertically extending Water tubes- 10 and a plurality of heat radiating fins 11 extending transversely of the tubes in vertical spaced relation to each other. The tubes 10 are elongated in cross section and extend in the general direction of flow of the air through the unit with the flat sides thereof parallel to each other. As will be observed from Figure 2, the tubes are arranged in a plurality of rows slightly offset from each other so that the space between adjacent tubes in one row is equally divided by the tubes in succeeding rows with substantially equal air spaces therebetween. In detail the tubes in the front row'designated generally in Figure 2 by the reference character 12 are succeeded by the tubes in the succeeding rows and owing to the fact that the tubes in the aforesaid rows are arranged in different portions oi' the air stream, relatively cool air will engage each of the tubes. It will further be observed from Figure 2 of the drawing that the long dimension of the tubes are arranged at a slight angle from the perpendicular to the front and rear faces of the unit so as to present a greater surface thereof to the air stream.

Referring now more in detail to the particular construction of the flnrs, it will be noted that each of the latter are of a length and width to embrace all of the tubes in the four rows andA are provided with apertures having flanges 1'7 at the marginal edges thereof adapted to be sleeved over the tubes for attachment thereto. As previously stated, it is one of the principal objects of the present invention to provide means upon the ns for creating a localized turbulence in the stream of air during its progress between the water tubes without obstructing the flow of theV air through the unit. The foregoing is accomplished in the present instance by embossing portions of the ns intermediate the apertures or tubes to form a pair of laterally spaced continuous offset oblique surfaces 18 and 19 between the adjacent sides of each pair of tubes. oblique surfaces 18 and 19 are of such character as to offer the minimum obstruction to the now of air between the tubesand do not constrict the cross sectional area of the air passages through the unit. In addition to the above, the offset oblique surfaces are so shaped as to produce vertical and lateral oscillation in the air current during its progress between the water tubes or in other words, creates a localized turbulence between the tubes which serve to carry the hot air flowing adjacent the side walls of the tubes away from the latter and replace the same with cooler air from the center of the air stream, thereby increasing the transfer of heat from the tubes` to the air.

As shown particularly in Figures 3, 4 and 5, the oiset oblique surfaces 18 and 19 are provided with upwardly'and rearwardly inclined front surfaces 20 terminating at the upper ends thereof in crests 21 arranged parallel with the tubes and connected to the general plane of the fin by down- The,

wardly and rearwardly inclined surfaces 22. The cross section at the crests of the embossments are clearly shown in Figure 3'as having obliquely sloping sides 24 which merge into the surfaces 22 and also into the general plane of the fin. As previously stated, the arrangement is such that the cross section of the air passage between adjacent water tubes in the same row remains constant, but the form of the surface both longitudinally and transversely is irregular so as to create localized turbulence between the tubes. It should also be understood that the air is deiiected during its passage through each of the rows due to the staggered arrangement shown in Figure 2, but without diminishing in'cross section so that the construction in its entirety will permit the flow of air from the front of the unit to the rear with the minimum resistance, but with the most intimate contact between all portions of the radiating ns.

It will further be observed that due to the double offset or embossment of the fins between each pair of tubes in the same row, a localized turbulence between each of the tubes will be eiected or, in other words, a mixing of the warm air adjacent the tubes with the relatively cool air in the center of the stream will result. While as stated above the embossments 18 and 19 serve to mix the air flowing between the tubes, nevertheless, it is to be noted that a certain amount of this air will be compelled to travel through the space between th embossments and owing to the distance between the central passage and the adjacent side Walls of the tubes this air stream will be relatively cool. The foregoing arrangement is particularly advantageous in a construction of the type shown herein wherein the tubes in each row are staggered relative to the tubes in succeeding rows as previously stated, since, when such is the case, the relatively cool stream of air flowing between the embossments in one row will be discharged against the tubes in the next succeeding row.

What I claim as my invention is:

1. In a heat exchange unit of the n and tube type, a plurality of rows of tubes, the tubes of each row being elongated in cross section in the direction of air flow and all of said tubes being slightly oblique to the front face of the unit and the tubes of succeeding rows being oifset with respect to the front row, fins parallelly arranged transversely of the tubes and having the surfaces between adjacent tubes embossed to form a pair of oiset portions extending in the direction of air flow and spaced laterally from each other as well as from the side walls of said tubes with the spaces between the inner walls of the embossments in registration with the spaces between the outer walls of the embossments and the adjacent walls of the tubes in the succeeding row.

2. In a heat exchange unit of the iin and tube type, a plurality of rows of tubes, the tubes in one row being offset with respect to the tubes in an adjacent row, fins arranged transversely of the tubes and having openings therein for receiving the latter, the surfaces of the fins between adjacent tubes in the first named row being embossed to form laterally spaced offset portions spaced laterally from each other as well as from the adjacent side walls of the tubes with the spaces between the embossments in registration with the spaces between the outer walls of the embossments and adjacent side Walls of the tubes in the succeeding row.

3. In a heat exchange unit of the iin and tube type, a plurality of tubes elongated in cross section in the direction of air flow, iins having spaced apertures therethrough for receiving said tubes, the surfaces of the ns between the side walls of adjacent tubes being embossed to form laterally spaced imperforate oiset portions also elongated in the direction of air flow and extending substantially parallel to the aforesaid side walls of the tubes, the offset portions having the outer walls thereof cooperating with the adjacent walls of said tubes to form air recesses for the passage of air and the inner walls of said portions cooperating with each other to form a central recess for the iiow of air.

WILLIAM C. RITTER. 

